401(k) · DOL Form 5500 · 2022

Board of Trustees of Supplemental Income Trust Fund 401(k) Plan

Data updated 2026-08-11

$1.4B
Total assets
28,894
Participants
99th
Percentile by assets
$49,220
Avg per participant
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Official DOL plan name: Supplemental Income 401(k) Plan · Sponsored by Board of Trustees of Supplemental Income Trust Fund · California · Transportation & Warehousing

$1.4B in assets, 28,894 participants

Board of Trustees of Supplemental Income Trust Fund's Supplemental Income 401(k) Plan reported $1.4B in total assets and 28,894 participants in its 2022 DOL Form 5500 filing, ranking in the 99th percentile by assets among filed plans. Figures are as reported by the plan sponsor to the Department of Labor, not audited or endorsed by PlainRetire.

  • 99th percentile by assets (of 139,126 plans)
  • #3,823 in Transportation & Warehousing (3,876 peers)

Coverage in California

Supplemental Income 401(k) Plan covers 28,894 participants in California, 46x the typical California plan (state average ~630 per filing). Assets: $1.4B.

$1.4B
total plan assets (2022 EOY)
28,894
covered participants
99th
percentile by assets (of 139,126 plans)
$49,220
avg assets per participant

The plan reported a net loss of $249M for the year, a single-year figure driven by markets and benefit payments, not a measure of plan health.

Participants vs California filers

In California, the average filing covers about 630 participants across 15,291 plans. Supplemental Income 401(k) Plan reports 28,894 participants - 46x that state average ($1.4B EOY assets).

California filing particulars

Total Assets (Beginning of Year)$1.7B
Net Assets (End of Year)$1.4B
Net Income-$249M
Employer EIN942554388
Plan Effective Date1995-01-01
Filing StatusFILING RECEIVED

Sponsor Plan History (Board of Trustees of Supplemental Income Trust Fund)

$1.2B$1.4B$1.6B$1.8B$2B 202220232024 $1.42B $1.87B ▲ +31.7%
Total plan assets by year, all Board of Trustees of Supplemental Income Trust Fund plans on file
Year Plans Participants Total Assets
2022 1 28,894 $1.4B
2023 1 30,285 $1.7B
2024 1 32,778 $1.9B

Nearby 401(k) Plans in California

Peer 401(k) plans, same state, same plan type, ranked by total assets.

Supplemental Income 401(k) Plan vs. nearby 401(k) plans in California, assets vs. participants

Supplemental Income 401(k) Plan vs. nearby 401(k) plans in California, assets vs. participants Scatter plot of 6 data points. 050000100000150000200000250000 -1001020304050 Total assets ($B) Participants Supplemental Income …Wells Fargo & Compan…Google LLC 401(k) Sa…Oracle Corporation 4…Chevron Employee Sav…Intel 401(k) Savings…
Supplemental Income 401(k) Plan vs. nearby 401(k) plans in California, assets vs. participants

Scale composition for Supplemental Income 401(k) Plan

Supplemental Income 401(k) Plan reports $1.4B in end-of-year assets across 28,894 participants (0.012% of the $12.3T held by all Form 5500 filers in the national rollup , and 0.031% of 93,925,755 covered participants) - about $49,220 per participant (36% of the national average assets-per-participant) . Net income for plan year 2022 was -$249M.

This plan identity (EIN 942554388, plan #002) has 3 Form 5500 filings on file from 2022 to 2024 , with end-of-year assets moving from $1.4B to $1.9B (+31.2%) while covered participants moved from 28,894 to 32,778 . Single-year sparse filers cannot show that trail.

Plan year Participants EOY assets Filing
2022 28,894 $1.4B This page
2023 30,285 $1.7B Open filing
2024 · index core 32,778 $1.9B Open filing

The same sponsor also keeps 1 other index-core plan on PlainRetire:

Similar-Sized 401(k) Plans Nationally

401(k) plans in other states closest to Supplemental Income 401(k) Plan by total assets, not by location.

Frequently Asked Questions

How did Supplemental Income 401(k) Plan assets move in 2022?
Supplemental Income 401(k) Plan pulled back noticeably - down 14.9% during 2022, from $1.7B to $1.4B. Reported net income was -$249M.
How have Board of Trustees of Supplemental Income Trust Fund plan assets changed over time?
Across 3 plan years on file (2022-2024), Board of Trustees of Supplemental Income Trust Fund's sponsor-wide assets grew 31.2%, from $1.4B to $1.9B.
Where does Supplemental Income 401(k) Plan rank by assets among Form 5500 filers?
Supplemental Income 401(k) Plan ranks in the 99th percentile by end-of-year assets among 139,126 plans that reported assets for plan year 2022 (among the largest 1% of all filed plans).
Which 401(k) plans are similar in size to Supplemental Income 401(k) Plan?
Among 401(k) plans in other states, the closest by assets is General Dynamics Corporation 401(k) Plan 3.0 in VA ($1.4B, 1,886 participants).

Filing takeaways

Ways to act on Supplemental Income 401(k) Plan's numbers.